The invention relates to a method and a device for operating an internal combustion engine for a road vehicle having an automatic transmission, it being detected if the road vehicle is rolling back while forward gear is engaged.
Such a method and device, respectively, are known from the German Patent 35 34 675 C2.
The object of the present invention is to further improve the above-indicated method and device.
The objective is achieved according to the invention by a method as recited in claim 1 and by a device as recited in claim 9. In this context, for operating an internal combustion engine for a road vehicle having an automatic transmission, it is detected whether there is back-rolling while forward gear is engaged, and upon detecting that the road vehicle is rolling back, the ignition angle of the internal combustion engine is altered to increase the engine torque. Thus, if back-rolling or the beginning of back-rolling is detected with forward gear engaged, then the ignition angle of the internal combustion engine is changed in such a way that the torque of the internal combustion engine is increased. In this manner, possible back-rolling of the road vehicle is eliminated more quickly and effectively than with the known method.
In an advantageous refinement of the invention, more air is metered into the internal combustion engine when it is detected that there is back-rolling with forward gear engaged. This additional measure effectively prevents back-rolling, even when there is a sharp incline.
One advantageous development of the invention provides for metering more air into the internal combustion engine when, after changing the ignition angle of the internal combustion to increase the engine torque, back-rolling is detected when forward gear is engaged.
In a further advantageous embodiment of the invention, a calculation is made of the increase in torque of the internal combustion engine necessary for preventing the road vehicle from rolling back while forward gear is engaged.
In another advantageous invention refinement, the increase in torque of the internal combustion engine which is possible by changing the ignition angle of the internal combustion engine is calculated.
A further advantageous development of the invention provides for metering more air into the internal combustion engine when the increase in torque of the internal combustion engine necessary for preventing the road vehicle from rolling back when forward gear is engaged is greater than the increase in internal-combustion-engine torque which is possible by changing the ignition angle of the engine.
According to another advantageous embodiment of the invention, the air is metered in with the aid of a bypass adjuster or by an electrically controllable throttle device (ETC) [electronic throttle control].